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December 1988

Oxygen Transmissibility, Thickness, and Water Content of Three Types of Collagen Shields

Author Affiliations

From the Jules Stein Eye Institute and Department of Ophthalmology, UCLA School of Medicine.

Arch Ophthalmol. 1988;106(12):1706-1708. doi:10.1001/archopht.1988.01060140878032

• Oxygen transmissibility, thickness, and water content were measured for three types of collagen shields: six of each type designed to dissolve in 12, 24, and 72 hours. Oxygen transmissibility was measured by a polarographic method at 35°C and was found to be 17.9, 17.3, and 23.8 × 10-9 cm mL O2/s mL mm Hg, respectively. Thicknesses were measured with an electronic gauge, and the central thicknesses of the 12-hour shields were found to be significantly greater (mean thickness, 0.19 mm) than the central thicknesses of the other two types (0.15 mm each). Water content, as measured by a hand refractometer, was found to be about 63% for all three types of shields, and no statistically significant differences were found. These measurements indicate that collagen shields behave like 63% water-content hydrogel contact lenses (oxygen permeability estimated at 27 × 10-11 cm2 mL O2/s mL mm Hg) with regard to oxygen transmission.